In recent years, with steadily increasing obesity, the World Health Organization (WHO) is warning countries around the world of an increased risk of lifestyle-related diseases, which are associated with obesity and include diabetes, hyperlipidemia, hypertension, arteriosclerosis, and fatty liver. Metabolic syndrome is a condition with, in addition to visceral fat accumulation, a combination of risk factors for arteriosclerosis, such as disorders of carbohydrate metabolism (abnormal glucose tolerance, diabetes), disorders of lipid metabolism (hypertriglyceridemia, hypercholesterolemia, and low levels of HDL cholesterol), and hypertension. Even if each of abnormalities (for example, in blood sugar or blood pressure) is mild and at the level of “Care Required” as a result of medical examination or the like, overlapping of such abnormalities tends to cause cardiovascular diseases. It is said that a human having 2 risk factors selected from obesity, hypertension, hyperglycemia, hypertriglyceridemia, and hypercholesterolemia is at the risk of cardiovascular diseases 10 times higher, and a human having 3 to 4 of such risk factors is at the risk 31 times higher than that of a human not having any of such risk factors.
The co-occurrence of obesity, diabetes, hypertension, and hyperlipidemia increases the risk of developing myocardial infarction or cerebral infarction, and therefore is called “Deadly Quartet”. Accumulation of visceral fat is considered to be the underlying cause eventually resulting in cardiovascular diseases, such as myocardial infarction and cerebral infarction. Therefore, for the prevention or amelioration of metabolic syndrome and also cardiovascular diseases, decreasing the accumulated visceral fat is important. Since obesity is caused by an imbalance between energy intake and expenditure, it is important, for the purpose of inhibiting obesity, to not only decrease energy intake but also increase energy consumption in basal metabolism or activity metabolism. For decreasing energy intake, low-energy replacements for fat and sugar are provided, but the taste or processability thereof in terms of food is not necessarily satisfactory.
Various measures have been proposed for the prevention of obesity. In recent years, in different kinds of food we regularly take, components having an effect of improving lipid metabolism, or preventing or ameliorating obesity have been found, and are expected to be useful for the prevention of obesity. The inventors focused attention on, among food components having such an effect, hesperidin, a low-molecular proanthocyanidin, and caffeine, which are known to have different working mechanisms with each other. Hesperidin is considered to have an effect of suppressing gene expression of fatty acid synthetase, an effect of increasing gene expression of carnitine palmitoyltransferases I and II, or the like, and thus to promote lipid metabolism (Non Patent Literature 1). Furthermore, it is reported that hesperidin and glucosyl hesperidin have an effect of reducing visceral fat or a waist size (Patent Literature 1). Low-molecular proanthocyanidins are known to have an effect of preventing or improving dysregulated production of adipocytokine and a thermogenic effect by inducing gene expression of uncoupling protein 1 (UCP1) (Non Patent Literature 2). Furthermore, they are known to have an effect of reducing body weight, abdominal circumference, visceral fat, and the like (Non Patent Literature 3). Caffeine is known to have an antagonist effect on adenosine receptors (Non Patent Literature 4), an effect of increasing circulating catecholamine level, and an effect of inhibiting phosphodiesterase activity, which activities facilitate lipid metabolism (Non Patent Literature 5), to inhibit hepatic lipogenesis, and to increase resting metabolic rate and energy consumption, resulting in decrease in body fat and body weight (Non Patent Literature 6). Thus, it is publicly known that each component by itself acts on lipid metabolism. However, there has been no report with regard to combining the components.